The U.S. Supreme Court declined Monday to step into a dispute over a Washington state law that requires political committees to disclose the names of donors behind ads critical of a candidate for elected office.

The Washington Supreme Court ruled last year that a political committee backed by the U.S. Chamber of Commerce broke state campaign finance laws when it refused to disclose the donors behind ads in the 2004 race for state attorney general.

The U.S. Chamber, working with a state group called the Voters Education Committee, paid for advertisements criticizing Democratic candidate Deborah Senn during the 2004 primary campaign.

The Voters Education Committee initially refused to register as a political campaign group with the state or reveal the source of its money.

The committee later reported a $1.5 million donation from the U.S. Chamber, which in turn declined to reveal any of its donors, saying it didn't raise any money specifically for the Senn campaign.

When the state Supreme Court took up the issue, it essentially confirmed that the Voters Education Committee did, in fact, have to reveal the group that paid for the ads that were critical of Senn's record.

The Legislature subsequently updated the campaign finance laws and required that organizations must disclose their donors in cases in which they raise money specifically for an issue ad.

Groups that paid for issue ads but do not raise money for those ads specifically are not subject to the reporting requirement.

Lori Anderson, a spokeswoman for the state Public Disclosure Commission, said the group is now looking into the possibility that those involved with the 2004 case may be subject to fines.

The U.S. justices did not comment on their action Monday.

The case is Voters Education Committee v. Washington State Public Disclosure Commission, 07-1153.